1. Field of the Invention
The present invention relates to a technique of correcting defective pixels present in a sensor.
2. Description of the Background Art
Sensors such as CCDs (Charge Coupled Devices) may contain defective pixels containing white spot defects, black spot defects or the like. Such defective pixels affect image quality, and thus require correction. For instance, CCD manufacturing plants employ a method of identifying addresses of such defective pixels and storing information on the addresses in a nonvolatile memory, so that CCDs are shipped with such information. Accordingly, when capturing images, digital cameras and the like use a method of identifying the position of a defective pixel based on such address information to correct the defective pixel by its neighboring pixels. This method requires a memory for storing the address information, which interferes with size reduction in circuit scale.
In this respect, Japanese Patent Application Laid-Open No. 2002-223391 discloses a technique of eliminating the need to provide a memory for storing address information.
On the other hand, Japanese Patent Application Laid-Open No. 2002-142157 discloses a technique of correcting defective pixels in accordance with the brightness level of images.
However, the conventional technique of eliminating the need to provide a memory for storing address information is disadvantageous in accuracy of correction, while the conventional technique of correcting defective pixels in accordance with the brightness level of images causes increase in circuit scale.